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T100 Valve Clearances #488767
05/04/13 10:30 pm
05/04/13 10:30 pm
Joined: Oct 2005
Posts: 572
Surrey UK
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Mattsta Offline OP
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The clearances specified for my 1952 T100 are 0.002 inlet and 0.004 exhaust (alloy barrel and head)

I've been having some problems with the inlet valve clearances becoming zero after a couple months which makes the bike a bastard to start when hot.

0.002 seems awful tight for an old engine. Does anyone run the early alloy pre-units with a more generous valve clearance on the inlet valves?


1952 Triumph T100 in a BSA A7 Frame
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Re: T100 Valve Clearances [Re: Mattsta] #488777
05/04/13 11:29 pm
05/04/13 11:29 pm
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scotland
triton thrasher Online content
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They'll stop closing up as the head and barrel settle down with re-torquing, but you can use looser clearances.


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: triton thrasher] #488799
05/05/13 1:35 am
05/05/13 1:35 am
Joined: Nov 2008
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Bishop, Calif.
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desco Offline
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Bishop, Calif.
From the Megacycle Cams instructions;
More clearance will sharpen up the low and mid range and reduce top end.
And;
There is usually a few thousands latitude between tight and loose.
This is for their #51005 cam which is set at .010", but why would it not apply to a stock cam?
I have loosened up the intake setting to .012 or 013 to lessen the overlap time and have seen a noticeable difference in performance at altitude.
There is no overlap on a stock cam but it will still keep both valves closed longer.


1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
Re: T100 Valve Clearances [Re: desco] #488803
05/05/13 2:18 am
05/05/13 2:18 am
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Vic. Australia
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Pete R - R.I.P. Offline
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Originally Posted By: desco

This is for their #51005 cam which is set at .010", but why would it not apply to a stock cam? - - - - - - - - - - - - - -
There is no overlap on a stock cam but it will still keep both valves closed longer.

The valve clearance must suit the opening/closing ramps of the cam you are using.It's obviously better to be a LITTLE loose,than a little tight.

There is plenty of overlap using stock cams.They may be 28/47 , 47/28 timings at 0.020" tappet lift.Seat-to-seat timing is even more.56 degrees overlap at the 0.020" mesurement,and probably 40 degrees more at seat-to-seat.

Re: T100 Valve Clearances [Re: Mattsta] #488838
05/05/13 12:00 pm
05/05/13 12:00 pm
Joined: Jul 2007
Posts: 891
Tasmania - Gateway to Antarcti...
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The manual I have states 0.010" for the alloy T100 running stock 3275 cams. This equates to a quarter turn on the adjuster thus negating the need for feeler gauges. I've been doing this for the last few years with no problems - noisy, but no problems.


"Live the life you love, find a god you trust and don't take it all too seriously"

Pre-units rule!

Mid fifties Triumph T100
Re: T100 Valve Clearances [Re: Tasman] #488851
05/05/13 2:29 pm
05/05/13 2:29 pm
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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Originally Posted By: Tasman
The manual I have states 0.010" for the alloy T100 running stock 3275 cams. This equates to a quarter turn on the adjuster thus negating the need for feeler gauges. I've been doing this for the last few years with no problems - noisy, but no problems.


Those cams were not stock on a 1952 T100, I'm pretty sure.


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: Mattsta] #488881
05/05/13 7:15 pm
05/05/13 7:15 pm
Joined: Jun 2007
Posts: 5,996
Maui Hawaii
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Maui Hawaii
I'm not sure when the ramp cams were introduced but it was exactly for that reason. The stock cams made so much noise with the alloy motor it was truly annoying.
BTW quietening ramps are nothing unusual. They should probably be on all cams, sporting or not. No reason not to.
It may be difficult to identify a true ramp cam from anything other than the part number. Someone with a lot of experience could do it, but the ordinary owner/wrench would have trouble with that.
It could be that you have sport cams, Tas, if they're noisy at .010 clearance.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: T100 Valve Clearances [Re: Mattsta] #488884
05/05/13 7:38 pm
05/05/13 7:38 pm
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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No 1952 Triumph has the cams it left the factory with. The commonest replacements are E3134 equivalents.


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: Mattsta] #488945
05/06/13 7:55 am
05/06/13 7:55 am
Joined: Oct 2005
Posts: 572
Surrey UK
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Mattsta Offline OP
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Surrey UK
I believe the 1952 T100 has pre-ramp cams so it doesn't have the later 0.010" clearances.

I have a 1955 repair manual and that states 0.010" with E3275 cams

I don't know what cams are fitted in my engine. The bottom end didn't need to be overhauled and I didn't record what cams are fitted

I'm going to run it with 0.010" clearances today and see how she runs

I stopped at Box Hill yesterday and she refused to start. I had an audience of people watching me trying to get her started

Typical!








Last edited by Mattsta; 05/06/13 8:11 am.

1952 Triumph T100 in a BSA A7 Frame
Re: T100 Valve Clearances [Re: Mattsta] #488985
05/06/13 4:19 pm
05/06/13 4:19 pm
Joined: Oct 2005
Posts: 572
Surrey UK
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Mattsta Offline OP
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Set the clearances to 0,004 inlet and 0.006 exhaust. Starts much better when hot.

Still a little concerned because I don't know what cams I have fitted. They are in fine condition so I didn't pay much attention to them. I'll need to pay close attention, perhaps check I still have a valve clearance with the engine hot.

But I did have my first breakdown today. Somehow, my homemade rubber gasket between the magneto cap and magneto body managed to escape and get itself all chewed up in the points. The bike died and ground to a halt just outside Dorking.

Fortunately, I had my satchel of tools with me and I managed to clean it all up and get her running again. Ran fine for the rest of the day. Gorgeous weather too. Happy days! smile


1952 Triumph T100 in a BSA A7 Frame
Re: T100 Valve Clearances [Re: Mattsta] #488993
05/06/13 5:13 pm
05/06/13 5:13 pm
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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scotland
It just fits into a groove in the lid, doesn't it.


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: triton thrasher] #488994
05/06/13 5:28 pm
05/06/13 5:28 pm
Joined: Oct 2005
Posts: 572
Surrey UK
M
Mattsta Offline OP
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Yeah.

It fitted fine when I made it but it seems it expanded and belled out into the points cavity and got snagged. It got well and truly chewed up.

So I cleaned everything up, got rid of all the smeg, lubed up the camring with a smear of engine oil and she ran like a charm all day.


1952 Triumph T100 in a BSA A7 Frame
Re: T100 Valve Clearances [Re: Mattsta] #489012
05/06/13 8:28 pm
05/06/13 8:28 pm
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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scotland
Something I've used in the past, that worked was a bit of the square section O-ring that comes with a replacement non-spin on oil filter for an automotive engine. Useless advice if you don't have any!


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: Mattsta] #489013
05/06/13 8:38 pm
05/06/13 8:38 pm
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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scotland
I've also used string!


Amateur Loctite enthusiast.
Re: T100 Valve Clearances [Re: Mattsta] #489014
05/06/13 8:40 pm
05/06/13 8:40 pm
Joined: Jun 2007
Posts: 5,996
Maui Hawaii
HawaiianTiger Offline
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Maui Hawaii
Man, That's one slick little ride.

I'm pretty sure you have ramp cams if they're marked E3275, but....

I always check and re-check my cams because.
1. They could be worn and not really show the signs.
2. They could have been re-profiled(ie. base circle ground)
3. They may have ambiguous part numbers (common)
4. They may be after-market and promise extra performance. These can be used even if you don't have the spec sheets by using the lobe center method of cam timing.
5. Since I've been on this forum I've learned a lot more, especially in regards to installing the tappet guides. If they're off,(it's easy to get wrong) cam degree findings will be skewed.

Cam degrees can be determined with the engine assembled and in the frame with a little bit of ingenuity.

Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: T100 Valve Clearances [Re: HawaiianTiger] #489099
05/07/13 6:57 am
05/07/13 6:57 am
Joined: Oct 2005
Posts: 572
Surrey UK
M
Mattsta Offline OP
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Surrey UK
I thought engines with ramped cams had a mark next to the engine number on the drive side crankcase?


1952 Triumph T100 in a BSA A7 Frame
Re: T100 Valve Clearances [Re: Mattsta] #489119
05/07/13 10:18 am
05/07/13 10:18 am
Joined: Jan 2005
Posts: 1,666
East Bethany New York
Dick Harris Offline
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East Bethany New York
Yes,looked like a spoked wheel. Dick

Re: T100 Valve Clearances [Re: Mattsta] #489124
05/07/13 11:15 am
05/07/13 11:15 am
Joined: Aug 2001
Posts: 7,550
scotland
triton thrasher Online content
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The wagon wheel mark means nothing 60 years later.


Amateur Loctite enthusiast.

Moderated by  John Healy 


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